I use Novell's Groupwise at work, and when out of the office often use their WebAccess. There is a problem with using Safari with Groupwise WebAccess where the key buttons that enable you to write new mail or create new calendar entries are not visible - they fall off the bottom of the page. Fortunately there is a solution:
Use the terminal or TinkerTool (see versionTracker.com for this) to enable the debug menu on Safari. Then set the user agent in the debug menu to Windows MSIE 6.0 before using Safari to view the WebAccess page.

For more on this issue, see the Macosxhints discussion